High capacity cable puller with multi-speed automatic shifting transmission

Abstract

A cable puller is provided to pull rope or cable where the cable puller includes a puller frame, a capstan rotatably mounted on the puller frame around a first axis of rotation, an output shaft rotatably mounted to the puller frame and coupled to the capstan, The capstan is configured to rotate when the output shaft is driven. A shift motor is configured to drive a cam to engage gearing coupled to the output shaft to a gear position comprising a low speed position, a medium speed position, and a high-speed position.

What is claimed is: 
     
       1. A cable puller configured to pull rope or cable comprising:
 a puller frame; 
 a capstan rotatably mounted on the puller frame around a first axis of rotation; 
 an output shaft rotatably mounted to the puller frame and coupled to the capstan, wherein the capstan rotates when the output shaft is driven; 
 a main motor configured to rotate the output shaft via gearing, wherein the gearing comprises
 a pinion shaft rotatably mounted to the puller frame, 
 a low speed pinion gear on the pinion shaft, the low speed gear being coupled to the main motor, 
 a low speed driven gear mounted on the output shaft by an overrunning clutch, the low speed driven gear being intermeshed with the low speed pinion gear, 
 a medium speed pinion gear on the pinion shaft, 
 a medium speed driven gear mounted on the output shaft by a bearing, the medium speed driven gear being intermeshed with the medium speed pinion gear, 
 a high-speed pinion gear on the pinion shaft, 
 a high-speed driven gear mounted on the output shaft by a bearing, the high-speed driven gear being intermeshed with the high-speed pinion gear; and 
 
 a shift motor configured to be coupled to one of medium speed driven gear and to the high-speed driven gear. 
 
     
     
       2. The cable puller of  claim 1 , further comprising
 a cam shaft coupled to the shift motor and configured to be rotated by the shift motor, the cam shaft having a pathway therein forming a cam surface; 
 a dog clutch mounted on the output shaft between the medium driven gear and the high-speed driven gear, the dog clutch being mounted for linear movement on the output shaft but being restrained from rotational movement on the output shaft; and 
 a cam follower coupled to the dog clutch and engaged with the cam surface, and 
 wherein rotation of the cam shaft by the shift motor causes the dog clutch to engage with one of the medium driven gear and the high-speed driven gear. 
 
     
     
       3. The cable puller of  claim 2 , wherein
 the dog clutch has a plurality of cogs extending from a first surface thereof and a plurality cogs extending from a second surface thereof; 
 the medium speed driven gear has a plurality cogs extending from a surface thereof which faces the first surface of the dog clutch, the cogs of the medium speed driven gear being engageable with the cogs on the first surface of the dog clutch; and 
 the high-speed driven gear has a plurality cogs extending from a surface thereof which faces the second surface of the dog clutch, the cogs of the high-speed driven gear being engageable with the cogs on the second surface of the dog clutch. 
 
     
     
       4. The cable puller of  claim 2 , wherein the output shaft has a non-cylindrical section between the medium driven gear and the high-speed driven gear, wherein the dog clutch is mounted on the non-cylindrical section by a non-cylindrical passageway provided through the dog clutch. 
     
     
       5. The cable puller of  claim 4 , wherein the non-cylindrical section is formed from a double-D shape. 
     
     
       6. The cable puller of  claim 2 , wherein the pinion shaft, the output shaft and the cam shaft are parallel to each other. 
     
     
       7. The cable puller of  claim 2 , wherein the overrunning clutch is one of a sprag clutch, a roller ramp clutch, a wrap spring clutch, and a wedge clutch. 
     
     
       8. The cable puller of  claim 1 , wherein the pinion shaft and the output shaft are parallel to each other. 
     
     
       9. The cable puller of  claim 1 , wherein the main motor and the low speed pinion gear are coupled together by at least one idler roller. 
     
     
       10. The cable puller of  claim 1 , wherein the overrunning clutch is one of a sprag clutch, a roller ramp clutch, a wrap spring clutch, and a wedge clutch. 
     
     
       11. The cable puller of  claim 1 , wherein the gearing further comprises a planetary gear set coupled to the output shaft and coupled to the capstan. 
     
     
       12. The cable puller of  claim 1 , wherein the main motor is one of a servomotor and stepper motor. 
     
     
       13. The cable puller of  claim 1 , wherein the shift motor is one of a servomotor and stepper motor. 
     
     
       14. The cable puller of  claim 1 , wherein the shift motor is a rotary solenoid. 
     
     
       15. The cable puller of  claim 1 , further comprising a boom mounted to the puller frame. 
     
     
       16. The combination of  claim 15 , further comprising a conduit engaging assembly mounted to the boom.